Short answer
Both are Bluetooth receivers, $199 against $219.
The FiiO BTR7 reaches 100 dB on 565 of the 567 models here, the iFi GO blu on 563.
| Specification | FiiO BTR7 | iFi GO blu |
|---|---|---|
| Power into 32Ω | 160 mW | 165 mW |
| Power into 150Ω | 35 mW | 35 mW |
| Power into 300Ω | 18 mW | 18 mW |
| Power into 600Ω | 9.0 mW | 8.8 mW |
| Output impedance | 1.2 Ω | 1.0 Ω |
| Output noise | 3.0 µV | not published |
| Price | $199 | $219 |
| Headphones it reaches 100 dB on out of 567 | 565 | 563 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | FiiO BTR7 | iFi GO blu |
|---|---|---|
| Socket | 4.4mm | 4.4mm |
| Power into 32Ω | 320 mW | 245 mW |
| Power into 300Ω | 40 mW | 26 mW derived |
| Output impedance | 2.8 Ω | 1.0 Ω |
| Output noise | 5.5 µV | not published |
| Headphones it reaches 100 dB on out of 567 | 565 | 565 |
Through the balanced sockets the two are level on the same test: each reaches 100 dB on 565 of the 567 models here. Derived figures are worked out from the loads the maker did publish.
| Load | FiiO BTR7 | iFi GO blu |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Published | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. FiiO BTR7 publishes at 32 Ω and at 300 Ω; iFi GO blu at 32 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 300 Ω only the FiiO BTR7 figure is the maker’s own. On those rows the derived number is the one to doubt first.
2 headphones reach 100 dB on the FiiO BTR7 but not on the iFi GO blu — Symphonium Crimson, Symphonium Helios.
23 headphones are left alone by the iFi GO blu under the one-eighth rule but coloured by the FiiO BTR7 (64 Audio Ocean, 64 Audio U18s, 64 Audio U6t, 20 more).
563 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Shure SE846: FiiO BTR7 has +34 dB of headroom there against +31 dB. 3 dB is twice the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for iFi GO blu because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | FiiO BTR7 headroom | iFi GO blu headroom | FiiO BTR7 hiss | iFi GO blu hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +34 dB damping | +31 dB | 24 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +14 dB damping | +11 dB | 4 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +20 dB | +20 dB | 2 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +15 dB | +15 dB | -2 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +13 dB | +12 dB | -3 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +9 dB | +9 dB | -9 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +4 dB | +4 dB | -13 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +2 dB | +2 dB | -15 dB | not published |
The iFi GO blu costs $20 more than the FiiO BTR7. Out of the 567 models here, that difference buys 23 more models left alone under the one-eighth rule.
It does not run one way only: the cheaper FiiO BTR7 drives 2 models to 100 dB that the iFi GO blu does not, which is the part worth checking against your own headphones before paying the difference.
Only published figures count here; blank axes are counted separately.
Each in full: FiiO BTR7 and iFi GO blu.